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A259919 Number of n X n upper triangular matrices (m_{i,j}) of nonnegative integers with 2 = Sum_{j=h..n} m_{h,j} - Sum_{i=1..h-1} m_{i,h} for all h in {1,...,n}. 1
1, 1, 3, 22, 351, 11275, 689146, 76718466, 15016410213, 5018597151979, 2793390337774000, 2534303740130716491, 3677548139455638020060, 8393668597786379602398164, 29683833854927200499142474520, 160463839044675821511377573062150, 1309702228155431081923017737636343876 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n) counts generalized Tesler matrices.  For the definition of Tesler matrices see A008608.

LINKS

Table of n, a(n) for n=0..16.

EXAMPLE

a(2) = 3: [1,1; 0,3], [2,0; 0,2], [0,2; 0,4].

MAPLE

b:= proc(n, i, l) option remember; (m-> `if`(m=0, 1,

      `if`(i=0, b(l[1]+2, m-1, subsop(1=NULL, l)), add(

      b(n-j, i-1, subsop(i=l[i]+j, l)), j=0..n))))(nops(l))

    end:

a:= n-> b(2, n-1, [0$(n-1)]):

seq(a(n), n=0..10);

CROSSREFS

Column k=2 of A259844.

Cf. A008608.

Sequence in context: A193193 A099750 A219268 * A275366 A196734 A271849

Adjacent sequences:  A259916 A259917 A259918 * A259920 A259921 A259922

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 08 2015

STATUS

approved

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Last modified February 26 20:23 EST 2020. Contains 332295 sequences. (Running on oeis4.)